Why should I blog?

I could use a little input here. I'm conflicted. Why blog? I tried it and quit once already. So this is my second attempt. Isn't there enough to do in a day already? How long can a person keep this up?

Do you blog for commercial, artistic, reasons, or PR, image? Do you do it to break out of an illustrator's isolation? Is blogging working for you? Thanks for humoring me. I'll get some art up on here soon.